The present invention relates to accumulating conveyors, and more particularly to a split-cam conveyor roller including a pair of roller portions rotatable relative one another between raised and lowered positions.
A wide variety of powered accumulating conveyors have been developed for transporting packages along a path. One particularly efficient construction is of the wheel, roller, and belt variety wherein a propelling member such as a belt is raised and lowered between transportation and accumulation positions, respectively. An exemplary construction is illustrated in U.S. Pat. No. 3,854,576 issued Dec. 17, 1974 to Bowman, entitled ECCENTRIC WHEEL ACCUMULATORS and assigned to the assignee of the present application. Such conveyors include a plurality of split-cam rollers each including two or more eccentric roller portions. When accumulation is desired, the roller portions are stopped with their peripheral portions of least radius facing upwardly to lower the drive belt out of engagement with the transported packages. When transportation is to be restarted, the rollers are released and the circular portions of the rollers force the drive belt upwardly into engagement with the propelled articles.
The Bowman split-cam roller was developed to alleviate a noise problem existent in the prior art of that time. In then-known conveyors, each conveyor roller utilized a one-piece cam; and most cams in a conveyor section would synchronize to lift the belt in unison to the conveyed articles creating a rhythmic noise that became annoying and distracting to those working in the area.
Although the Bowman construction was developed to address this rhythmic noise problem, the assignee of the present application has found that the Bowman construction does not maintain the continuous circular drive surface desired during transportation. The desired circular configuration is usually maintained for several revolutions, and then the eccentric portions shift to approach a configuration wherein all the flats are aligned. The construction therefore produces unpredictable lifting of the belt. Although the rhythmic noise problem was solved, Bowman's rollers created an equally loud but random or arhythmic noise undersirable to workers in the area.